Green’s Dictionary of Slang

(drugs) a tablet of Ritalin.

1983		New Society 11 Aug. 203/1: What’ve you got? [...] I’ll swap you if you’ve got any Rit [....] (Ritalin a stimulant).
1997		L. Pettiway Workin’ It 202: Yeah, he was doing it all. Ritz and tees, you know. I never saw him get high in front of me.
2002		(con. 1981) W. Self Dorian 46: He was known as the Dikes and Rits man [...] This was eminently suitable, for the Dicanol and Ritalin that the Doctor sold were stolen or defrauded.